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Texas Instruments LMR51406XDBVR
- Part No.:
- LMR51406XDBVR
- Manufacturer:
- Texas Instruments
- Package:
- SOT-23-6
- Datasheet:
-
LMR51406XDBVR.pdf
- Description:
- IC REG BUCK ADJ 600MA SOT23-6
- Quantity:
- Payment:
- Shipping:
Inventory:2,955
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Product details
Overview
LMR51406XDBVR from Texas Instruments is a 4V–42V input, 0.6A synchronous buck DC/DC converter in SOT-23-6 package, featuring PFM operation, 400kHz fixed switching frequency, ±1.5% reference voltage accuracy, and monotonic start-up with prebiased output-designed for rugged industrial power conditioning in PLCs and smart meters.
For engineers reviewing the LMR51406XDBVR datasheet, LMR51406XDBVR pinout, LMR51406XDBVR application, or LMR51406XDBVR equivalent, key selection considerations include its 80ns minimum on-time, hiccup-mode short-circuit protection, precision enable with adjustable UVLO, integrated bootstrap driver, and thermal shutdown at 165°C junction temperature.
Technical Context
The LMR51406XDBVR employs fixed-frequency peak-current mode control with internal compensation and PFM light-load efficiency optimization. It integrates high-side (0.7Ω) and low-side (0.36Ω) MOSFETs, supports adjustable output voltage via 0.8V reference, and uses cycle-by-cycle current limiting with valley current detection for robust overload handling.
Its functional block includes precision enable logic, internal soft-start (2.3ms), UVLO with 3.82V rising threshold and 0.25V hysteresis, and frequency foldback to extend duty cycle range-enabling stable regulation down to 0.8V output across 4V–42V input while maintaining 98% max duty cycle capability.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 42V - supports wide industrial unregulated rails including 12V, 24V, and 36V systems without external pre-regulation. |
| Output Current | 0.6A continuous - sufficient for powering microcontrollers, sensors, and isolated gate drivers in compact industrial modules. |
| Switching Frequency | 400kHz - enables use of small, low-profile inductors (e.g., 2.2µH) while balancing EMI and efficiency trade-offs. |
| Reference Voltage | 0.8V ±1.5% - ensures tight output regulation (±2.5%) over –40°C to +150°C junction temperature range. |
| Min ON Time | 80ns - allows high step-down ratios (e.g., 24V→3.3V) without frequency foldback at full load. |
| Thermal Shutdown | 165°C with 20°C hysteresis - protects against sustained overload or poor PCB thermal design in enclosed enclosures. |
| Quiescent Current | 26.5–40µA in PFM mode - extends battery life in always-on monitoring applications like smart meter backup supplies. |
Pinout & Package
SOT-23-6 (DBV) package: 2.90mm × 2.80mm footprint, thermally enhanced for 0.6A operation in space-constrained industrial PCBs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CB | Bootstrap capacitor connection | Connects 100nF ceramic capacitor to SW; provides gate drive voltage for internal high-side MOSFET. |
| GND | Power ground | Common return for internal low-side FET, CIN, and COUT; requires shortest possible trace to minimize noise and EMI. |
| FB | Feedback input | Monitors output via resistor divider; sets VOUT = 0.8V × (1 + RFBT/RFBB); must not be shorted to GND during operation. |
| EN | Precision enable | Logic-controlled startup: EN ≥1.227V enables regulation; EN ≤1.0V disables; supports system-level UVLO via external divider. |
| VIN | Input supply | Connects to 4–42V source and local 10µF ceramic bypass capacitor; powers internal LDO and high-side driver. |
| SW | Switch node | Drives external power inductor; connects internally to source of high-side FET and drain of low-side FET; high dv/dt node requiring careful layout. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated synchronous rectification | Eliminates external Schottky diode, reducing BOM count and improving full-load efficiency by ~5% vs. asynchronous designs. |
| Internal compensation | Enables stable loop response with only FB resistors and output capacitor-no external compensation network required. |
| PFM light-load operation | Boosts efficiency to >85% at 1mA load (VOUT=5V), critical for low-power sensor nodes and standby circuits. |
| Hiccup-mode short-circuit protection | Shuts down for 150ms after 256 consecutive current-limit cycles, limiting average power dissipation during sustained faults. |
| Monotonic start-up with prebias support | Prevents output voltage undershoot or reverse current when powered into an already-biased rail-essential for hot-swap and redundancy systems. |
Applications
| PLC Digital I/O Module Power | Smart Meter MCU Supply |
|---|---|
|
Use Scenario: Powers 3.3V microcontroller and isolated RS-485 transceivers from 24V field bus in DIN-rail mounted programmable logic controllers. IC Role / Device Role / Timing Role: Primary non-isolated buck regulator delivering regulated 3.3V at up to 0.6A with fast transient response to digital I/O switching loads. Use Value: 400kHz switching enables compact 2.2µH inductor; PFM mode maintains >80% efficiency at µA-level sleep currents between polling intervals. |
Use Scenario: Generates 5V rail for metrology SoC and real-time clock in Class 0.5 smart electricity meters operating from 12V battery backup. IC Role / Device Role / Timing Role: Secondary buck stage stepping down from primary 12V battery to stable 5V, supporting precise ADC reference and RTC oscillator. Use Value: ±1.5% reference tolerance ensures <±0.5% output drift over temperature-meeting IEC 62053-21 accuracy requirements for energy measurement. |
| Industrial HMI Display Backlight Driver | Factory Automation Sensor Node |
|
Use Scenario: Supplies 12V to LED backlight strings in 7-inch TFT displays used in panel-mounted human-machine interfaces. IC Role / Device Role / Timing Role: High-efficiency buck converter configured for adjustable 12V output, driving constant-current LED drivers with minimal thermal rise. Use Value: 42V max input withstands 36V nominal supply transients; 98% max duty cycle supports 12V output even at VIN = 12.5V (low-dropout condition). |
Use Scenario: Powers ultra-low-power wireless sensor nodes (BLE/Zigbee) deployed in predictive maintenance vibration monitors on rotating machinery. IC Role / Device Role / Timing Role: Primary power management IC converting 24V plant supply to 3.3V for MCU, RF transceiver, and MEMS accelerometer. Use Value: 26.5µA quiescent current in PFM mode extends 2000mAh LiSOCl₂ battery life to >10 years in periodic wake-up operation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LMR51406XFDBVR | FPWM mode instead of PFM; fixed 400kHz operation regardless of load; higher light-load ripple but tighter regulation. | Better suited for noise-sensitive analog circuits (e.g., precision ADC references) where constant frequency is mandatory. | Select when output voltage stability under dynamic load outweighs light-load efficiency priority. |
| LMR51410XDBVR | 1A output rating (vs. 0.6A); identical pinout, package, and feature set; higher RDS(on) values optimized for higher current. | Required for applications needing >0.6A continuous output, such as multi-rail industrial controllers or dual-core MCUs. | Drop-in upgrade path if future design scaling or margin expansion is anticipated-same layout, no redesign needed. |
Compared with LMR51406XFDBVR, the LMR51406XDBVR delivers superior light-load efficiency but sacrifices output voltage ripple consistency; compared with LMR51410XDBVR, it offers lower thermal stress and cost in sub-0.6A applications while sharing identical footprint and control interface.
Availability
LMR51406XDBVR is available at Aetrix Electronics and suitable for PLC digital I/O modules, smart meter MCU supplies, and industrial HMI display power requiring stable component supply, long-term lifecycle assurance, and automotive-grade reliability validation.
Supply support for LMR51406XDBVR includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management technologies, with decades of industrial-grade product development expertise.
The LMR514xx family is part of TI's SIMPLE SWITCHER® portfolio-designed specifically for rugged, easy-to-deploy DC/DC conversion in harsh industrial environments where reliability, small size, and minimal external components are critical.
FAQ
What is the maximum input voltage the LMR51406XDBVR can withstand without damage?
The LMR51406XDBVR has an absolute maximum input voltage rating of 45V, with transient protection rated up to 50V for durations under 10ns. Its recommended operating input range is 4V to 42V, making it suitable for 24V and 36V industrial buses subject to load-dump spikes. Operation beyond 42V should be limited to brief transients and verified against thermal limits in the target PCB layout.
Does the LMR51406XDBVR require external compensation components?
No, the LMR51406XDBVR features fully internal compensation, eliminating the need for external Type-II or Type-III compensation networks. This simplifies design, reduces bill-of-materials count, and improves stability across varied output capacitor ESR/ESL values-including ceramic, polymer, and tantalum types-without tuning.
How does the precision enable (EN) pin function in the LMR51406XDBVR?
The EN pin on the LMR51406XDBVR provides a precision enable threshold: device turns on when EN voltage exceeds 1.227V (typical) and shuts down when EN falls below 1.0V (typical). It supports system-level undervoltage lockout via an external resistor divider and must never be left floating. The pin draws only 10–50nA, enabling low-power sequencing control.
What protection features are built into the LMR51406XDBVR?
The LMR51406XDBVR integrates cycle-by-cycle overcurrent limiting, hiccup-mode short-circuit protection (150ms off-time), thermal shutdown at 165°C with 20°C hysteresis, input UVLO (3.82V rising threshold), and bootstrap undervoltage lockout. These features collectively prevent damage during fault conditions while maintaining safe restart behavior after fault clearance.
Can the LMR51406XDBVR operate with a prebiased output during start-up?
Yes, the LMR51406XDBVR supports monotonic start-up into a prebiased output-a critical feature for hot-swap and redundant power systems. Its internal soft-start circuit ramps the reference voltage without forcing reverse current into the output capacitor, preventing potential damage to downstream circuitry or upstream sources during live insertion.
LMR51406XDBVR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- SOT-23-6
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4V
- Voltage - Input (Max):
- 42V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 28V
- Current - Output:
- 600mA
- Frequency - Switching:
- 400kHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-6
LMR51406XDBVR FAQ
1.How can I place an order for LMR51406XDBVR through Aetrix?
Please submit a Request for Quotation (RFQ) for LMR51406XDBVR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LMR51406XDBVR reliable?
The price and inventory of LMR51406XDBVR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LMR51406XDBVR is usually 5 days.
3.What payment methods are accepted for LMR51406XDBVR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LMR51406XDBVR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LMR51406XDBVR?
LMR51406XDBVR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LMR51406XDBVR order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LMR51406XDBVR?
For technical support, including LMR51406XDBVR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LMR51406XDBVR requirements.
6.How does Aetrix verify that LMR51406XDBVR is sourced from the original manufacturer or authorized distributors?
All LMR51406XDBVR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LMR51406XDBVR meets industry standards.
7.What is the process for return or replacement of LMR51406XDBVR?
All LMR51406XDBVR units undergo pre-shipment inspection (PSI). If there is an issue with LMR51406XDBVR, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LMR51406XDBVR part is unused and in its original packaging.
Return procedure for LMR51406XDBVR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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